[V1] VLM preprocessor hashing (#11020)

Signed-off-by: Roger Wang <ywang@roblox.com>
Signed-off-by: Alexander Matveev <alexm@neuralmagic.com>
Co-authored-by: Michael Goin <michael@neuralmagic.com>
Co-authored-by: Roger Wang <ywang@roblox.com>

vllm/engine/arg_utils.py

@@ -143,6 +143,7 @@ class EngineArgs:
     tokenizer_pool_extra_config: Optional[Dict[str, Any]] = None
     limit_mm_per_prompt: Optional[Mapping[str, int]] = None
     mm_processor_kwargs: Optional[Dict[str, Any]] = None
+    mm_cache_preprocessor: bool = False
     enable_lora: bool = False
     enable_lora_bias: bool = False
     max_loras: int = 1
@@ -593,6 +594,12 @@ class EngineArgs:
             type=json.loads,
             help=('Overrides for the multimodal input mapping/processing, '
                   'e.g., image processor. For example: {"num_crops": 4}.'))
+        parser.add_argument(
+            '--mm-cache-preprocessor',
+            action='store_true',
+            help='If true, then enables caching of the multi-modal '
+            'preprocessor/mapper. Otherwise, the mapper executes each time'
+            ', and for better performance consider enabling frontend process.')
 
         # LoRA related configs
         parser.add_argument('--enable-lora',
@@ -965,6 +972,7 @@ class EngineArgs:
             use_async_output_proc=not self.disable_async_output_proc,
             config_format=self.config_format,
             mm_processor_kwargs=self.mm_processor_kwargs,
+            mm_cache_preprocessor=self.mm_cache_preprocessor,
             override_neuron_config=self.override_neuron_config,
             override_pooler_config=self.override_pooler_config,
         )